NutriStack
Sulforaphane and Vitamin C, a synergy.
When sulforaphane is taken in precursor (glucoraphanin) form, vitamin C can improve its conversion to the active molecule by supporting the myrosinase enzyme that performs the hydrolysis. The conversion step is the rate-limiting factor for precursor-based products: glucoraphanin preparations lacking active myrosinase yield only roughly 10 percent of dose as sulforaphane, whereas an active myrosinase source can raise this to around 40 percent. Ascorbate is routinely co-included with myrosinase in bioavailability formulations, and many commercial broccoli-extract products deliberately co-formulate vitamin C plus a myrosinase source. The effect is most relevant for glucoraphanin-based supplements and for sulforaphane generated from food (broccoli, sprouts); pre-formed stabilized sulforaphane depends less on this step. This is a favorable absorption and conversion synergy, not a risk.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Sulforaphane and Vitamin C
- Pair type
- Synergy
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Synergy · Emerging evidence
Synergy
What is happening. When sulforaphane is taken in precursor (glucoraphanin) form, vitamin C can improve its conversion to the active molecule by supporting the myrosinase enzyme that performs the hydrolysis. The conversion step is the rate-limiting factor for precursor-based products: glucoraphanin preparations lacking active myrosinase yield only roughly 10 percent of dose as sulforaphane, whereas an active myrosinase source can raise this to around 40 percent. Ascorbate is routinely co-included with myrosinase in bioavailability formulations, and many commercial broccoli-extract products deliberately co-formulate vitamin C plus a myrosinase source. The effect is most relevant for glucoraphanin-based supplements and for sulforaphane generated from food (broccoli, sprouts); pre-formed stabilized sulforaphane depends less on this step. This is a favorable absorption and conversion synergy, not a risk.
Mechanism. Most supplemental sulforaphane is delivered as its inactive precursor glucoraphanin (broccoli seed or sprout extract), which must be hydrolyzed by the enzyme myrosinase to release active sulforaphane. Ascorbic acid (vitamin C) can act as a cofactor that modulates myrosinase activity at low concentrations, helping drive the hydrolysis step and increasing the yield of sulforaphane. With cofactor support present during hydrolysis, conversion of glucoraphanin to absorbable sulforaphane and its glutathione metabolites can rise, improving systemic bioavailability of the active compound.
Recommendation. If using a glucoraphanin or broccoli-extract product, take it with vitamin C (a typical 250 to 500 mg dose, or a vitamin-C-containing food or juice) at the same time, ideally alongside an active myrosinase source in the formula. Timing matters: take them together rather than hours apart so vitamin C is present during hydrolysis. No benefit is expected to be lost if you also already use a pre-converted, stabilized sulforaphane product, where the conversion step is bypassed.
Minimum separation. Take together
Sources (2)
- Fahey et al., Sulforaphane bioavailability from glucoraphanin-rich broccoli: control by active endogenous myrosinase, PLOS ONE, 2015
- Pharmacology literature on ascorbate as a low-concentration modulator of myrosinase activity during glucosinolate hydrolysis
Stack Score
How this pair moves the number.
Effect on the composite score
If both Sulforaphane and Vitamin C are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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